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I don't like to admit this, but at this point honestly I think ipv6 is largely a failure, and I say this as someone that wrote a blog post for APNIC on how to t

I don't like to admit this, but at this point honestly I think ipv6 is largely a failure, and I say this as someone that wrote a blog post for APNIC on how to turn on ipv6. I'll get endless pushback for this, but the reality is that adoption isn't at 100%, it very closely needs to be, and there are still entire ISPs that only assign ipv4, to say nothing of routers people are buying and installing that don't have ipv6 enabled out of the box. A much better solution here would have been an incredibly conservative "written on a napkin" change to ipv4 to expand the number of available address space. It still would have been difficult to adopt, but it would have the benefit of being a simple change to a system everyone already understands and on top of a stack that largely already exists. I'm not proposing to abandon ipv6, but at this point I'm really not sure how we proceed here. The status quo is maintaining two separate competing protocols forever, which was not the ultimate intention.

hypeatei 9mo ago
> A much better solution here would have been an incredibly conservative change to ipv4 to expand the number of available address space "And what do you base this belief on? Fact is you'd run into exactly the same problems as with IPv6. Sure, network-enabled software might be easier to rewrite to support 40-bit IPv4+, but any hardware-accelerated products (routers, switches, network cards, etc.) would still need replacement (just as with IPv6), and you'd still need everyone to be assigned unique IPv4+ addresses in order to communicate with each other (just as with IPv6)."[0] 0: https://news.ycombinator.com/item?id=37120422 https://news.ycombinator.com/item?id=37120422
- redox99 9mo ago
  Hardware would catch up. And IPv4 would never go away. If you connect to 1.1.1.1 it would still be good ole IPv4. You would only have in addition the option to connect to 1.1.1.1.1.1.1.2 if the entire chain supports it. And if not, it could still be worked around through software with proxies and NAT.
  - hypeatei 9mo ago
    So... just a less ambitious IPv6 that would still require dual-stack networking setups? The current adoption woes would've happened regardless, unless someone comes up with a genius idea that doesn't require any configuration/code changes.
    - krupan 9mo ago
      I disagree. The current adoption woes are exactly because IPv6 is so different from IPv4. Everyone who tries it out learns the hard way that most of what they know from IPv4 doesn't apply. A less ambitious IPv4 is exactly what we need in order to make any progress
      - sgjohnson 9mo ago
        But that is a bug in history. IPv6 was standardized BEFORE NAT. “most what they know from IPv6” is just NAT. > A less ambitious IPv4 is exactly what we need in order to make any progress but we’re already making very good progress with IPv6? Global traffic to Google is >50% IPv6 already.
        btilly 9mo ago
        Current statistics are that a bit over 70% of websites are IPv4 only. A bit under 30% allow IPv6. IPv6 only websites are a rounding error. Therefore if I'm on an IPv6 phone, odds are very good that my traffic winds up going over IPv4 internet at some point. We're 30 years into the transition. We are still decades away from it being viable for servers to run IPv6 first. You pretty much have to do IPv4 on a server. IPv6 is an afterthought.
        sgjohnson 9mo ago
        > We are still decades away from it being viable for servers to run IPv6 first. Just put Cloudflare in front of it. You don’t need to use IPv4 on servers AT ALL. Only on the edge. You can easily run IPv6-only internally. It’s definitely not an afterthought for any new deployments. In fact there’s even a US gov’t mandate to go IPv6-first. It’s the eyeballs that need IPv4. It’s a complete non-issue for servers.
- avidiax 9mo ago
  > Fact is you'd run into exactly the same problems as with IPv6. If you treat IPv4 addresses as a routable prefix (same as today), then the internet core routers don't change at all. Only the edge equipment would need to be IPv4+ aware. And even that awareness could be quite gradual, since you would have NAT to fall back on when receiving an IPv4 classic packet at the network. It can even be customer deployed. Add an IPv4+ box on the network, assign it the DMZ address, and have it hand out public IPV4+ addresses and NAT them to the local IPv4 private subnet. IPv6 seems to be a standard that suffered from re-design by committee. Lots of good ideas were incorporated, but it resulted in a stack that had only complicated backwards compatibility. It has taken the scale of mobile carriers to finally make IPv6 more appealing in some cases than IPv4+NAT, but I think we are still a long way from any ISP being able to disable IPv4 support.
  - sgjohnson 9mo ago
    > Only the edge equipment would need to be IPv4+ aware. And even that awareness could be quite gradual, since you would have NAT to fall back on when receiving an IPv4 classic packet at the network. It can even be customer deployed. Add an IPv4+ box on the network, assign it the DMZ address, and have it hand out public IPV4+ addresses and NAT them to the local IPv4 private subnet. Congratulations, you’ve re-invented CGNAT, with none of the benefits, and the additional hassle of it being an entirely new protocol! No. No “extra bits” on an IPv4 address would have ever worked. NAT itself is a bug. Suggesting that as an intentional design is disingenuous.
    - avidiax 9mo ago
      I have not "reinvented CGNAT". It is hierarchal public addressing similar to IPv4 and IPv6. The edge router has an IPv4+ subnet (either a classic v4 address, or part of a v4+ address). It maintains an L2 routing table with ARP+, and routes IPv4+ packets to the endpoint without translation. Private subnetting and NAT is only needed to support legacy IPv4 clients. CGNAT pools IPv4 public addresses and has an expanded key for each connection, and translates either 4 to 6 or into a private IPv4 subnet. My proposal needs no pooling and only requires translation if the remote host is IPv4 classic and the edge router is not assigned a full IPv4+/24.
- btilly 9mo ago
  I agree with that belief, and I've been saying it for over 20 years. I base it on comparing how the IPv2 to IPv4 rollout went, versus the IPv4 to IPv6 rollout. The fact that it was incredibly obvious how to route IPv2 over IPv4 made it a no-brainer for the core Internet to be upgraded to IPv4. By contrast it took over a decade for IPv6 folks to accept that IPv6 was never going to rule the world unless you can route IPv4 over it. Then we got DS-Lite. Which, because IPv6 wasn't designed to do that, adds a tremendous amount of complexity. Will we eventually get to an IPv6 only future? We have to. There is no alternative. But the route is going to be far more painful than it would have been if backwards compatibility was part of the original design. Of course the flip side is that some day we don't need IPv4 backwards compatibility. But that's still decades from now. How many on the original IPv6 will even still be alive to see it?
  - Macha 9mo ago
    The IPv2 to IPv4 migration involved sysadmins at less than 50 institutions (primarily universities and research labs), updating things they considered to be a research project, that didn’t have specialised network hardware that knew anything about IP, and any networked software was primarily written either by the sysadmins themselves or people that one of them could walk down the corridor to the office of. Oh, and several months of downtime if someone was too busy to update right now was culturally acceptable. It’s not remotely the same environment as existed at the time of IPv6 being designed
- almosthere 9mo ago
  The IPv4+ could pass through a router that doesn't know about it - the cloud host that receives that packet could interpret it in a special way, in fact you could stuff additional data into the next layer of the stack for routing - it's not like many services beyond TCP would need to support the scheme.
  - viraptor 9mo ago
    > The IPv4+ could pass through a router that doesn't know about it It couldn't do that reliably. We don't have any flags left for that that. Options are not safe. We've got one reserved flag which is anyways set to 0, so that's not safe either.
    - magicalhippo 9mo ago
      > We don't have any flags left for that that. There's the reserved bit (aka the evil bit[1]). Are you saying gear out there drops packets with reserved bit set to 1? Wouldn't surprise me, just curious. Seems like IPv4+ would have been a good time to use that bit. Any IPv4+ packets could have more flags in the + portion of the header, if needed. [1]: https://en.wikipedia.org/wiki/Evil_bit https://en.wikipedia.org/wiki/Evil_bit
      - viraptor 9mo ago
        That bit is currently defined as "Bit 0: reserved, must be zero", so there will be network gear out there, that either drops the packet otherwise or resets the bit to 0 when forwarding.
        magicalhippo 9mo ago
        That makes it effectively impossible to ever use then, so a waste of a bit. Too bad they made that mistake when writing the spec. Would have been better if they specified it like most APIs, ie ignore if you get it, carry it if you forward, and set it to zero if you send it.
- morshu9001 9mo ago
  Hardware support for ipv6 hasn't been the limiting factor in a long time. Users higher on the stack don't want to adopt something that makes so many unnecessary changes.
- solarkraft 9mo ago
  You’re focusing on the technical difficulty of implementing it in software. This is not the problem. IPv6 support is now present in almost every product, but people still refuse to set it up because it’s so different to what they’re used to (I’m not arguing whether the changes are good - they’re just changes). IPv4+ would’ve solved this social problem.
  - doctorpangloss 9mo ago
    There’s absolutely, utterly zero chance IPv4+ would be adopted. CGNAT is the solution to the social problem. I don’t even buy your way of thinking - unlike an “engineering” solution or an “incentives” solution, the problem with “social solutions I speculate about” is: they offer nothing until implemented. They are literally all the same, no difference between the whole world of social solutions, until they are adopted. They are meaningless. They’re the opposite of plans. Like what’s the difference between IPv4+, which doesn’t exist, and “lets pass a law that mandates ipv6 support”? Nothing. This is what the mockery of “just pass a law” is about. I don’t like those guys, but they are right: it’s meaningless.
    - solarkraft 9mo ago
      This is a good point. The same “why should I migrate” would affect it. However, it being so close to the predecessor, it would be much easier to do so, catching way more people who are on the fence.
School-Cotton 9mo ago
ipv6 adoption is still steadily rising. Not as fast as anyone hoped, but at least steadily. There is no way it can be abandoned at this point even if we wanted to.
- aurumque 9mo ago
  I wonder if it could still be usurped by another standard that is somehow more popular. If adoption of that leapfrogs over IPV6 then maybe it will have just been a waypoint along the way.
  - krupan 9mo ago
    This absolutely can and should happen
  - jandrese 9mo ago
    What would a new standard do that would make it more popular? IPv6, for all its faults, is designed to be the last Internet Protocol we will ever need.
    - aboardRat4 9mo ago
      In the new standard every publicly routable packet will include a cryptographically signed passport number of the responsible person. Then the government could, for example, limit criminals' access to the internet by mandating that their packets be dropped on most major ISPs, or at least deprioritised.
      - jandrese 9mo ago
        Funny enough I actually looked at a scheme for corporate networks where your personal corporate ID is encoded as part of the host bits of the IPv6 packet and policy could be applied based on who you are instead of what machine it is (or both). It was kind of neat but the complexity was too high for it to gain traction, and also it turns out that most corporate networks are allergic to IPv6 and government networks doubly so.
onionisafruit 9mo ago
Circa 1999 I was working for Cisco as a sysadmin. I got my CCNP through internal training and considered making a career of network administration, but ipv6 changed my mind. It seemed so much more difficult and unpleasant to deal with. I didn't want that to be my day to day work. I think the same thing happens on a different scale with ISPs. They don't want to deal with it until they have to for largely the same reason.
- sgjohnson 9mo ago
  > It seemed so much more difficult and unpleasant to deal with. In my experience it’s much easier and much more pleasant do deal with. Every VLAN is a /64 exactly. Subnetting? Just increment on a nibble boundary. Every character can be split 16 ways. It’s trivial. You don’t even need to use a subnet calculator for v6, because you can literally do that in your head. Network of 2a06:a003:1234:5678::555a:bcd7/64? Easy - the first 4 octets. Network of 10.254.158.58/27? Your cheapest shotgun and one shell please.
  - tguvot 9mo ago
    remembering 10.254.158.58. Easy - the first 4 octets. remembering 2a06:a003:1234:5678::555a:bcd7/64. Your cheapest shotgun and one shell please.
    - sgjohnson 9mo ago
      If you have a /48 assigned, you’ll burn the prefix in your brain. Leaves 16 bits for the network address. e.g. you’ll get 2a06:a003:1234::/48 from the ISP - what you’ll really need to remember is the 2a06:a003:1234:xxxx::/64 part. And I use the VLAN id for the xxxx part. Trivial.
      - tguvot 9mo ago
        and xx is birtday ?
  - krupan 9mo ago
ajross 9mo ago
I wouldn't say "failure". There are many, many IPv6 client devices out there, mostly on mobile networks. And it works great and they do well and the tools all support it very well. But IPv4 will never, ever die. The rise of NAT as a pervasive security paradigm[1] basically neuters the one true advantage IPv6 brought to the table by hiding every client environment behind a single address, and the rise of "cloud everything" means that no one cares enough about reaching peer devices anyway. Just this morning my son asked me to share a playlist, so of course I just send him a link to a YouTube Music URL. Want to work on a spreadsheet for family finances with your spouse in the next room? It lives in a datacenter in The Dalles. [1] And yes, we absolutely rely as a collective society on all our local devices being hidden. Yes, I understand how it works, and how firewalls could do this with globally writable addresses too, yada yada. But in practice NAT is best. It just is.
- JeremyNT 9mo ago
  > I wouldn't say "failure". There are many, many IPv6 client devices out there, mostly on mobile networks. Honestly it's a huge success due to this fact alone. IPv6 is failure only if you measure success by replacing IPv4 or if you called "time" on it before the big mobile providers rolled it out. The fact that all mobile phones support it and many mobile networks exclusively deploy it tells you what you really need to know. IPv6 is a backbone of the modern Internet for clients, even if your servers don't have to care about it due to nat64.
  - morshu9001 9mo ago
    The IETF explicitly says the goal of IPv6 is to replace IPv4, not to run alongside it. We're very far from that goal. https://datatracker.ietf.org/doc/html/rfc8200#page-4 https://datatracker.ietf.org/doc/html/rfc8200#page-4
bigfatkitten 9mo ago
IPv6's failure was mostly caused by the IETF's ivory tower dwellers, who seem to generally have no practical experience or understanding whatsoever of how networks are actually built and run today, especially at the small to mid scale. Small site multihoming, for example, is an absolute disaster. Good luck if you're trying to add a cellular backup to your residential DSL connection. IETF says you should either have multiple routers advertising multiple provider-assigned prefixes (a manageability nightmare), or that you should run BGP with provider independent address space; have fun getting your residential ISP or cellular carrier onboard with this idea.
- nine_k 9mo ago
  > a cellular backup to your residential DSL connection Hmm, what's the problem? I suppose your home devices should never be exposed to the public internet, and should only be accessible via a VPN like Wireguard. NAT64 is a thing if your home network is IPv4. BTW what's the trouble with multi-homing? Can't an interface have two separate IPv6 addresses configured on it, the same way as IPv4 addresses?
  - bigfatkitten 9mo ago
    > BTW what's the trouble with multi-homing? Can't an interface have two separate IPv6 addresses configured on it, the same way as IPv4 addresses? Because it breaks your network when that router goes away. Your switch ACLs, firewall rules, and DNS records all become invalid because they contain addresses that no longer exist, that your devices continue trying to reach anyway.
    - patmorgan23 9mo ago
      You should be using dynamic DNS and firewall rules should be on the subnet boundary in this scenario, any decent firewall (including referee PFsense/OpnSense) support ACLs that follow IPv6 address changes.
      - hdgvhicv 9mo ago
kmeisthax 9mo ago
Stripped of all the other baggage that came with it (e.g. SLAAC, IPsec, etc) IPv6 is an incredibly conservative addressing extension. The only thing even more conservative than v6 would have been to drop the lower 64 bits of the address and the associated EUI-64 local addressing scheme. Which... to be fair, that turned out to be a very bad idea, but the length of the field isn't what was holding up v6 adoption. I suspect by "incredibly conservative" you mean "backwards compatible", which... no. You can't make an addressing extension backwards compatible with hardware that doesn't read all of the address. Of course, we did that anyway with CGNAT, and predictably it causes huge problems with end-to-end connectivity, which is the whole point of IPv6. You're probably thinking more along the lines of an explicit "extension addressing header" for v4. Problem is, that'd mean a more awkward version of IPv6's /64 address split[0], combined with all sorts of annoying connectivity problems. The same corporate middleboxes that refuse to upgrade to IPv6 also choke on anything that isn't TCP traffic to ports 80 and 443. So you'd need Happy Eyeballs style racing between CGNAT IPv4 and "extended IPv4". Also, that would just be a worse version of 6in4. Because they also thought of just tunneling IPv6 traffic in IPv4 links. I don't think you understand how incredibly conservative IPv6 actually is. The problem with "incredibly conservative" IP extensions is that nothing beats the conservatism of doing literally nothing. IT infrastructure is never ripped out and replaced unless there is a business case for doing so. The current problem with IPv6 adoption is that nobody has yet said "let's stop processing IPv4 traffic", they've only said "let's get more dual-stack hosts online", which is a process that only asymptotes to 100% IPv6, and never reaches it. IPv4 was not the first version of the Internet protocol. That honor goes to Network Control Protocol (NCP). The reason why we don't have an asymptotic long tail of Internet hosts still demanding NCP connectivity is because this was back when "having a connection to the Internet" meant "having a connection to ARPANET". The US military could just refuse to process NCP packets and actively did this to force people onto IPv4. Now imagine if someone big like Google said "we're going to stop accepting IPv4 connections" - people would jump onto v6 immediately. [0] Let's say we add a 32-bit extension header onto IPv4
- krupan 9mo ago
  "Stripped of all the other baggage that came with it..." But that baggage is a huge part of the problem. Almost nothing you know about IPv4 applies when you switch to IPv6, and most of us found that out the hard way when we tried to make the switch. Leaves a pretty bad taste in your mouth.
culi 9mo ago
The only solution is a gov't mandate. China went from almost no adoption to leading the world in adoption (77% of all Chinese internet users) in a few years because they explicitly prioritized it in their last 5-year-plan. The ISPs aren't gonna do it on their own.
- p_l 9mo ago
  US government has finally learnt from how vendors break the mandates and there's now IPv6 mandate if you want to sell to federal government, and waivers are only available for buyers not vendors, and individually every time.
alphazard 9mo ago
> I'm not proposing to abandon ipv6, but at this point I'm really not sure how we proceed here. The status quo is maintaining two separate competing protocols forever, which was not the ultimate intention. The end game will be a cryptographically large address space allocated based on some cryptographic operation, rather than a committee carving up the space arbitrarily. Tor already does this, addresses allocation is not a problem. I think they used to use hashes, but now use Ed25519 public keys. Obviously, Tor is not suitable for most tasks. No one should have to pay for the extra latency if they don't need the anonymity. The real problem is routing in these address spaces, and there have been a few projects like CJDNS which try to solve it.
morshu9001 9mo ago
Imagine every address along a major road is 3 digits, and some shortsighted post office code assumes 3. Your business is 845 Oak St. One day they say hey, this road is getting too long, let's update that code to support 10 digits and we never worry about this again. Oh and btw, your address is now 9245593924 Oak St.
MagicMoonlight 9mo ago
Yep, just call it IPv8 and make it double the length of IPv4. Ultimately, an address system that replaces “1.1.1.1” with “JEDBSO:7372B6D6A:727:8:72829:762927” or whatever just isn’t viable. Even AWS doesn’t let you use IPv6 with anything… and they charge you for using IPv4 now.
- free_bip 9mo ago
  This is the first time I've heard this critique. I think most people don't care if their IP address is easily human readable/memorizable. In my experience when people do deal with ipv4/v6 addresses directly, they just copy-paste.
  - Nursie 9mo ago
    I can keep a v4 in my head, briefly. v6 not so much. Or shout one across a room to someone. Of course that’s due to the relatively small amount of information it contains and having a larger address space is always going to break that.
  - krupan 9mo ago
    Sure most people don't care, just the ones who have to figure out why it's not working, and man does it suck for them.
  - benjiro 9mo ago
    Man, readability of IP numbers is a important thing. You are not always in a situation where you can simply copy the address. I can tell you what is what simply from the Ipv4 address, but when its IPv6, my dyslexia is going to kick my behind. Readability reduces errors, and IPv6 is extreme unreadable. And we have not talked yet about pre-fix, post-fix, that range :: indicator, ... Reading a Ipv6 network stack is just head pain inducing, where as Ipv4 is not always fun but way more readable. They where able to just extend IPv4 with a extra range, like 1.192.120.121.122, 2.... and you have another 255 Ipv's ... They did the same thing for the Belgium number plates (1-abc-001) and they will run out in the year 11990 somewhere lol... The problem is, that Ipv6 is over engineered, and had no proper transition from Ipv4 > Ipv6 build in, and that is why 30 years later, we are still dealing with the fallout.
imoverclocked 9mo ago
I think this is defeatist talk where it’s not warranted. I remember IPX networks in the 90s were still a thing because people believed they could eke out a little more performance for their games. It’s taking a long time to move to IPv6 in some parts of the world. eg: anyone who doesn’t feel the pain of the IPv4 address crunch likely due to having a large chunk to begin with. Many influential organizations in North America definitely fall in that category. IPv6 is a success IMHO because it is used in so many places. Google’s IPv6 traffic graph shows close to 50% adoption and still trending up. We can’t possibly expect the world to be near 100% overnight… the internet is a big place with the whole spectrum of humans influencing IT; There will always be someone who will cling to IPv4 for dear life.
thayne 9mo ago
I actually think it would have had a better chance of success if ipv6 had embraced the breaking changes to add some killer feature that would have made it worthwhile to upgrade even for entities who didn't need to worry about running out of ipv4 addresses. I'm not sure what that feature would be though.
- imoverclocked 9mo ago
  This is actually unwanted in a dual-stack world. Once you have divergent behaviors on your networks, you have a complex/weakened security model. Networking should be boring.
Asooka 9mo ago
I've been thinking we could simply extend the ipv4 address to be 11 bytes by (ab)using the options field. That is, add an option that holds more bytes for the source and destination address, which are to be appended to the address already present in the header. I am thinking that since an option starts with 2 bytes and everything must be padded to a multiple of 4 bytes, we can add 16 bytes to the packet, which would hold 7 extra address bytes per source and destination, giving us 11 byte addresses. ISPs would be given a bunch of 4-byte toplevel addresses and can generate 7-byte suffixes dynamically for their subscribers, in a way that is almost the same as CGNAT used today but without all the problems that has. Most routers will only need to be updated to pass along the option and otherwise route as normal, because the top level address is already enough to route the packet to the ISP's routers. Then only at the edge will you need to do extra work to route the packet to the host. Not setting the option would be equivalent to setting it to all 0s, so all existing public hosts will be automatically addressable with the new scheme. There will of course need to be a lot more work done for DNS, DHCP, syntax in programs, etc, but it would be a much easier and more gradual transition than IPv6 is demanding.
- fruitworks 9mo ago
  I don't think so. It would be more confusion because no one will know if a network is ipv4 or ipv4+, leading to edge case bugs and confusion and people will similarly be lazy and choose to only implement ipv4 knowing it will always be reverse compatible and the cost is transferred to the consumer. Plus, it's only 2048x the address space. It's within the realm of possibility that we will need to upgrade again once this place is swarming with robots.
  - GordonS 9mo ago
    x2048 is a lot though! Maybe we should let the robots figure out their own solution, rather than trying to make every atom on Earth individually addressable :)
bit_logic 9mo ago
This whole discussion reminds me of the beautiful design of UTF-8. They used the lower bits to be ASCII which made backwards compatibility so much easier. It also reminds me of the failure of Intels Itanium and the success of AMD x64. Engineers often want to abandon backwards compatibility to make a new "beautiful" design, but it's the design that has full backwards compatibility that's actual impressive.
- krupan 9mo ago
  So well said! Those are great comparisons.
- x0x0 9mo ago
  It reminds me of python 3. Basically, a huge chunk of people (in my case, scientific programming) get an enormous mess and nothing at all of value until... 3.6 maybe (the infix matrix mult operator). Stunningly, people weren't enthused about this deal.
- liquidpele 9mo ago
  It would maybe be okay at the router to break some things, but ffs even in software I have to choose? Why do I need both ping and ping6 this is stupid!! They really screwed up by making it a breaking change to the OS and not just internet routing.
  - elcritch 9mo ago
    The whole ping vs ping6 seems more likely than lazy developers.
  - Dagger2 9mo ago
    They didn't screw up. They made it a breaking change to OSs because it had to be a breaking change to OSs. If anyone screwed up here, it was the people who made v4, not the ones that made v6. For ping, I think it originally had different binaries because ICMPv4 and ICMPv6 are different protocols, but Linux has had a dual-stack `ping` binary for a very long time now. You can just use `ping` for either address family.
vachina 9mo ago
Truth is there are too many devices that only speak IPv4 or have untested IPv6 stack. People still can’t even agree on how ipv6 address is represented.
- iov6throwaway 9mo ago
  People have totally agreed on how IPv6 addresses are represented.

hypeatei 9mo ago

> A much better solution here would have been an incredibly conservative change to ipv4 to expand the number of available address space "And what do you base this belief on? Fact is you'd run into exactly the same problems as with IPv6. Sure, network-enabled software might be easier to rewrite to support 40-bit IPv4+, but any hardware-accelerated products (routers, switches, network cards, etc.) would still need replacement (just as with IPv6), and you'd still need everyone to be assigned unique IPv4+ addresses in order to communicate with each other (just as with IPv6)."[0] 0: https://news.ycombinator.com/item?id=37120422 https://news.ycombinator.com/item?id=37120422

redox99 9mo ago
Hardware would catch up. And IPv4 would never go away. If you connect to 1.1.1.1 it would still be good ole IPv4. You would only have in addition the option to connect to 1.1.1.1.1.1.1.2 if the entire chain supports it. And if not, it could still be worked around through software with proxies and NAT.
- hypeatei 9mo ago
  So... just a less ambitious IPv6 that would still require dual-stack networking setups? The current adoption woes would've happened regardless, unless someone comes up with a genius idea that doesn't require any configuration/code changes.
  - krupan 9mo ago
    I disagree. The current adoption woes are exactly because IPv6 is so different from IPv4. Everyone who tries it out learns the hard way that most of what they know from IPv4 doesn't apply. A less ambitious IPv4 is exactly what we need in order to make any progress
    - sgjohnson 9mo ago
      But that is a bug in history. IPv6 was standardized BEFORE NAT. “most what they know from IPv6” is just NAT. > A less ambitious IPv4 is exactly what we need in order to make any progress but we’re already making very good progress with IPv6? Global traffic to Google is >50% IPv6 already.
      - btilly 9mo ago
        Current statistics are that a bit over 70% of websites are IPv4 only. A bit under 30% allow IPv6. IPv6 only websites are a rounding error. Therefore if I'm on an IPv6 phone, odds are very good that my traffic winds up going over IPv4 internet at some point. We're 30 years into the transition. We are still decades away from it being viable for servers to run IPv6 first. You pretty much have to do IPv4 on a server. IPv6 is an afterthought.
        sgjohnson 9mo ago
        > We are still decades away from it being viable for servers to run IPv6 first. Just put Cloudflare in front of it. You don’t need to use IPv4 on servers AT ALL. Only on the edge. You can easily run IPv6-only internally. It’s definitely not an afterthought for any new deployments. In fact there’s even a US gov’t mandate to go IPv6-first. It’s the eyeballs that need IPv4. It’s a complete non-issue for servers.
avidiax 9mo ago
> Fact is you'd run into exactly the same problems as with IPv6. If you treat IPv4 addresses as a routable prefix (same as today), then the internet core routers don't change at all. Only the edge equipment would need to be IPv4+ aware. And even that awareness could be quite gradual, since you would have NAT to fall back on when receiving an IPv4 classic packet at the network. It can even be customer deployed. Add an IPv4+ box on the network, assign it the DMZ address, and have it hand out public IPV4+ addresses and NAT them to the local IPv4 private subnet. IPv6 seems to be a standard that suffered from re-design by committee. Lots of good ideas were incorporated, but it resulted in a stack that had only complicated backwards compatibility. It has taken the scale of mobile carriers to finally make IPv6 more appealing in some cases than IPv4+NAT, but I think we are still a long way from any ISP being able to disable IPv4 support.
- sgjohnson 9mo ago
  > Only the edge equipment would need to be IPv4+ aware. And even that awareness could be quite gradual, since you would have NAT to fall back on when receiving an IPv4 classic packet at the network. It can even be customer deployed. Add an IPv4+ box on the network, assign it the DMZ address, and have it hand out public IPV4+ addresses and NAT them to the local IPv4 private subnet. Congratulations, you’ve re-invented CGNAT, with none of the benefits, and the additional hassle of it being an entirely new protocol! No. No “extra bits” on an IPv4 address would have ever worked. NAT itself is a bug. Suggesting that as an intentional design is disingenuous.
  - avidiax 9mo ago
    I have not "reinvented CGNAT". It is hierarchal public addressing similar to IPv4 and IPv6. The edge router has an IPv4+ subnet (either a classic v4 address, or part of a v4+ address). It maintains an L2 routing table with ARP+, and routes IPv4+ packets to the endpoint without translation. Private subnetting and NAT is only needed to support legacy IPv4 clients. CGNAT pools IPv4 public addresses and has an expanded key for each connection, and translates either 4 to 6 or into a private IPv4 subnet. My proposal needs no pooling and only requires translation if the remote host is IPv4 classic and the edge router is not assigned a full IPv4+/24.
btilly 9mo ago
I agree with that belief, and I've been saying it for over 20 years. I base it on comparing how the IPv2 to IPv4 rollout went, versus the IPv4 to IPv6 rollout. The fact that it was incredibly obvious how to route IPv2 over IPv4 made it a no-brainer for the core Internet to be upgraded to IPv4. By contrast it took over a decade for IPv6 folks to accept that IPv6 was never going to rule the world unless you can route IPv4 over it. Then we got DS-Lite. Which, because IPv6 wasn't designed to do that, adds a tremendous amount of complexity. Will we eventually get to an IPv6 only future? We have to. There is no alternative. But the route is going to be far more painful than it would have been if backwards compatibility was part of the original design. Of course the flip side is that some day we don't need IPv4 backwards compatibility. But that's still decades from now. How many on the original IPv6 will even still be alive to see it?
- Macha 9mo ago
  The IPv2 to IPv4 migration involved sysadmins at less than 50 institutions (primarily universities and research labs), updating things they considered to be a research project, that didn’t have specialised network hardware that knew anything about IP, and any networked software was primarily written either by the sysadmins themselves or people that one of them could walk down the corridor to the office of. Oh, and several months of downtime if someone was too busy to update right now was culturally acceptable. It’s not remotely the same environment as existed at the time of IPv6 being designed
almosthere 9mo ago
The IPv4+ could pass through a router that doesn't know about it - the cloud host that receives that packet could interpret it in a special way, in fact you could stuff additional data into the next layer of the stack for routing - it's not like many services beyond TCP would need to support the scheme.
- viraptor 9mo ago
  > The IPv4+ could pass through a router that doesn't know about it It couldn't do that reliably. We don't have any flags left for that that. Options are not safe. We've got one reserved flag which is anyways set to 0, so that's not safe either.
  - magicalhippo 9mo ago
    > We don't have any flags left for that that. There's the reserved bit (aka the evil bit[1]). Are you saying gear out there drops packets with reserved bit set to 1? Wouldn't surprise me, just curious. Seems like IPv4+ would have been a good time to use that bit. Any IPv4+ packets could have more flags in the + portion of the header, if needed. [1]: https://en.wikipedia.org/wiki/Evil_bit https://en.wikipedia.org/wiki/Evil_bit
    - viraptor 9mo ago
      That bit is currently defined as "Bit 0: reserved, must be zero", so there will be network gear out there, that either drops the packet otherwise or resets the bit to 0 when forwarding.
      - magicalhippo 9mo ago
        That makes it effectively impossible to ever use then, so a waste of a bit. Too bad they made that mistake when writing the spec. Would have been better if they specified it like most APIs, ie ignore if you get it, carry it if you forward, and set it to zero if you send it.
morshu9001 9mo ago
Hardware support for ipv6 hasn't been the limiting factor in a long time. Users higher on the stack don't want to adopt something that makes so many unnecessary changes.
solarkraft 9mo ago
You’re focusing on the technical difficulty of implementing it in software. This is not the problem. IPv6 support is now present in almost every product, but people still refuse to set it up because it’s so different to what they’re used to (I’m not arguing whether the changes are good - they’re just changes). IPv4+ would’ve solved this social problem.
- doctorpangloss 9mo ago
  There’s absolutely, utterly zero chance IPv4+ would be adopted. CGNAT is the solution to the social problem. I don’t even buy your way of thinking - unlike an “engineering” solution or an “incentives” solution, the problem with “social solutions I speculate about” is: they offer nothing until implemented. They are literally all the same, no difference between the whole world of social solutions, until they are adopted. They are meaningless. They’re the opposite of plans. Like what’s the difference between IPv4+, which doesn’t exist, and “lets pass a law that mandates ipv6 support”? Nothing. This is what the mockery of “just pass a law” is about. I don’t like those guys, but they are right: it’s meaningless.
  - solarkraft 9mo ago
    This is a good point. The same “why should I migrate” would affect it. However, it being so close to the predecessor, it would be much easier to do so, catching way more people who are on the fence.

School-Cotton 9mo ago

ipv6 adoption is still steadily rising. Not as fast as anyone hoped, but at least steadily. There is no way it can be abandoned at this point even if we wanted to.

aurumque 9mo ago
I wonder if it could still be usurped by another standard that is somehow more popular. If adoption of that leapfrogs over IPV6 then maybe it will have just been a waypoint along the way.
- krupan 9mo ago
  This absolutely can and should happen
- jandrese 9mo ago
  What would a new standard do that would make it more popular? IPv6, for all its faults, is designed to be the last Internet Protocol we will ever need.
  - aboardRat4 9mo ago
    In the new standard every publicly routable packet will include a cryptographically signed passport number of the responsible person. Then the government could, for example, limit criminals' access to the internet by mandating that their packets be dropped on most major ISPs, or at least deprioritised.
    - jandrese 9mo ago
      Funny enough I actually looked at a scheme for corporate networks where your personal corporate ID is encoded as part of the host bits of the IPv6 packet and policy could be applied based on who you are instead of what machine it is (or both). It was kind of neat but the complexity was too high for it to gain traction, and also it turns out that most corporate networks are allergic to IPv6 and government networks doubly so.

onionisafruit 9mo ago

Circa 1999 I was working for Cisco as a sysadmin. I got my CCNP through internal training and considered making a career of network administration, but ipv6 changed my mind. It seemed so much more difficult and unpleasant to deal with. I didn't want that to be my day to day work. I think the same thing happens on a different scale with ISPs. They don't want to deal with it until they have to for largely the same reason.

sgjohnson 9mo ago
> It seemed so much more difficult and unpleasant to deal with. In my experience it’s much easier and much more pleasant do deal with. Every VLAN is a /64 exactly. Subnetting? Just increment on a nibble boundary. Every character can be split 16 ways. It’s trivial. You don’t even need to use a subnet calculator for v6, because you can literally do that in your head. Network of 2a06:a003:1234:5678::555a:bcd7/64? Easy - the first 4 octets. Network of 10.254.158.58/27? Your cheapest shotgun and one shell please.
- tguvot 9mo ago
  remembering 10.254.158.58. Easy - the first 4 octets. remembering 2a06:a003:1234:5678::555a:bcd7/64. Your cheapest shotgun and one shell please.
  - sgjohnson 9mo ago
    If you have a /48 assigned, you’ll burn the prefix in your brain. Leaves 16 bits for the network address. e.g. you’ll get 2a06:a003:1234::/48 from the ISP - what you’ll really need to remember is the 2a06:a003:1234:xxxx::/64 part. And I use the VLAN id for the xxxx part. Trivial.
    - tguvot 9mo ago
      and xx is birtday ?
- krupan 9mo ago

ajross 9mo ago

I wouldn't say "failure". There are many, many IPv6 client devices out there, mostly on mobile networks. And it works great and they do well and the tools all support it very well. But IPv4 will never, ever die. The rise of NAT as a pervasive security paradigm[1] basically neuters the one true advantage IPv6 brought to the table by hiding every client environment behind a single address, and the rise of "cloud everything" means that no one cares enough about reaching peer devices anyway. Just this morning my son asked me to share a playlist, so of course I just send him a link to a YouTube Music URL. Want to work on a spreadsheet for family finances with your spouse in the next room? It lives in a datacenter in The Dalles. [1] And yes, we absolutely rely as a collective society on all our local devices being hidden. Yes, I understand how it works, and how firewalls could do this with globally writable addresses too, yada yada. But in practice NAT is best. It just is.

JeremyNT 9mo ago
> I wouldn't say "failure". There are many, many IPv6 client devices out there, mostly on mobile networks. Honestly it's a huge success due to this fact alone. IPv6 is failure only if you measure success by replacing IPv4 or if you called "time" on it before the big mobile providers rolled it out. The fact that all mobile phones support it and many mobile networks exclusively deploy it tells you what you really need to know. IPv6 is a backbone of the modern Internet for clients, even if your servers don't have to care about it due to nat64.
- morshu9001 9mo ago
  The IETF explicitly says the goal of IPv6 is to replace IPv4, not to run alongside it. We're very far from that goal. https://datatracker.ietf.org/doc/html/rfc8200#page-4 https://datatracker.ietf.org/doc/html/rfc8200#page-4

bigfatkitten 9mo ago

IPv6's failure was mostly caused by the IETF's ivory tower dwellers, who seem to generally have no practical experience or understanding whatsoever of how networks are actually built and run today, especially at the small to mid scale. Small site multihoming, for example, is an absolute disaster. Good luck if you're trying to add a cellular backup to your residential DSL connection. IETF says you should either have multiple routers advertising multiple provider-assigned prefixes (a manageability nightmare), or that you should run BGP with provider independent address space; have fun getting your residential ISP or cellular carrier onboard with this idea.

nine_k 9mo ago
> a cellular backup to your residential DSL connection Hmm, what's the problem? I suppose your home devices should never be exposed to the public internet, and should only be accessible via a VPN like Wireguard. NAT64 is a thing if your home network is IPv4. BTW what's the trouble with multi-homing? Can't an interface have two separate IPv6 addresses configured on it, the same way as IPv4 addresses?
- bigfatkitten 9mo ago
  > BTW what's the trouble with multi-homing? Can't an interface have two separate IPv6 addresses configured on it, the same way as IPv4 addresses? Because it breaks your network when that router goes away. Your switch ACLs, firewall rules, and DNS records all become invalid because they contain addresses that no longer exist, that your devices continue trying to reach anyway.
  - patmorgan23 9mo ago
    You should be using dynamic DNS and firewall rules should be on the subnet boundary in this scenario, any decent firewall (including referee PFsense/OpnSense) support ACLs that follow IPv6 address changes.
    - hdgvhicv 9mo ago

kmeisthax 9mo ago

Stripped of all the other baggage that came with it (e.g. SLAAC, IPsec, etc) IPv6 is an incredibly conservative addressing extension. The only thing even more conservative than v6 would have been to drop the lower 64 bits of the address and the associated EUI-64 local addressing scheme. Which... to be fair, that turned out to be a very bad idea, but the length of the field isn't what was holding up v6 adoption. I suspect by "incredibly conservative" you mean "backwards compatible", which... no. You can't make an addressing extension backwards compatible with hardware that doesn't read all of the address. Of course, we did that anyway with CGNAT, and predictably it causes huge problems with end-to-end connectivity, which is the whole point of IPv6. You're probably thinking more along the lines of an explicit "extension addressing header" for v4. Problem is, that'd mean a more awkward version of IPv6's /64 address split[0], combined with all sorts of annoying connectivity problems. The same corporate middleboxes that refuse to upgrade to IPv6 also choke on anything that isn't TCP traffic to ports 80 and 443. So you'd need Happy Eyeballs style racing between CGNAT IPv4 and "extended IPv4". Also, that would just be a worse version of 6in4. Because they also thought of just tunneling IPv6 traffic in IPv4 links. I don't think you understand how incredibly conservative IPv6 actually is. The problem with "incredibly conservative" IP extensions is that nothing beats the conservatism of doing literally nothing. IT infrastructure is never ripped out and replaced unless there is a business case for doing so. The current problem with IPv6 adoption is that nobody has yet said "let's stop processing IPv4 traffic", they've only said "let's get more dual-stack hosts online", which is a process that only asymptotes to 100% IPv6, and never reaches it. IPv4 was not the first version of the Internet protocol. That honor goes to Network Control Protocol (NCP). The reason why we don't have an asymptotic long tail of Internet hosts still demanding NCP connectivity is because this was back when "having a connection to the Internet" meant "having a connection to ARPANET". The US military could just refuse to process NCP packets and actively did this to force people onto IPv4. Now imagine if someone big like Google said "we're going to stop accepting IPv4 connections" - people would jump onto v6 immediately. [0] Let's say we add a 32-bit extension header onto IPv4

krupan 9mo ago
"Stripped of all the other baggage that came with it..." But that baggage is a huge part of the problem. Almost nothing you know about IPv4 applies when you switch to IPv6, and most of us found that out the hard way when we tried to make the switch. Leaves a pretty bad taste in your mouth.

culi 9mo ago

The only solution is a gov't mandate. China went from almost no adoption to leading the world in adoption (77% of all Chinese internet users) in a few years because they explicitly prioritized it in their last 5-year-plan. The ISPs aren't gonna do it on their own.

p_l 9mo ago
US government has finally learnt from how vendors break the mandates and there's now IPv6 mandate if you want to sell to federal government, and waivers are only available for buyers not vendors, and individually every time.

alphazard 9mo ago

> I'm not proposing to abandon ipv6, but at this point I'm really not sure how we proceed here. The status quo is maintaining two separate competing protocols forever, which was not the ultimate intention. The end game will be a cryptographically large address space allocated based on some cryptographic operation, rather than a committee carving up the space arbitrarily. Tor already does this, addresses allocation is not a problem. I think they used to use hashes, but now use Ed25519 public keys. Obviously, Tor is not suitable for most tasks. No one should have to pay for the extra latency if they don't need the anonymity. The real problem is routing in these address spaces, and there have been a few projects like CJDNS which try to solve it.

morshu9001 9mo ago

Imagine every address along a major road is 3 digits, and some shortsighted post office code assumes 3. Your business is 845 Oak St. One day they say hey, this road is getting too long, let's update that code to support 10 digits and we never worry about this again. Oh and btw, your address is now 9245593924 Oak St.

MagicMoonlight 9mo ago

Yep, just call it IPv8 and make it double the length of IPv4. Ultimately, an address system that replaces “1.1.1.1” with “JEDBSO:7372B6D6A:727:8:72829:762927” or whatever just isn’t viable. Even AWS doesn’t let you use IPv6 with anything… and they charge you for using IPv4 now.

free_bip 9mo ago
This is the first time I've heard this critique. I think most people don't care if their IP address is easily human readable/memorizable. In my experience when people do deal with ipv4/v6 addresses directly, they just copy-paste.
- Nursie 9mo ago
  I can keep a v4 in my head, briefly. v6 not so much. Or shout one across a room to someone. Of course that’s due to the relatively small amount of information it contains and having a larger address space is always going to break that.
- krupan 9mo ago
  Sure most people don't care, just the ones who have to figure out why it's not working, and man does it suck for them.
- benjiro 9mo ago
  Man, readability of IP numbers is a important thing. You are not always in a situation where you can simply copy the address. I can tell you what is what simply from the Ipv4 address, but when its IPv6, my dyslexia is going to kick my behind. Readability reduces errors, and IPv6 is extreme unreadable. And we have not talked yet about pre-fix, post-fix, that range :: indicator, ... Reading a Ipv6 network stack is just head pain inducing, where as Ipv4 is not always fun but way more readable. They where able to just extend IPv4 with a extra range, like 1.192.120.121.122, 2.... and you have another 255 Ipv's ... They did the same thing for the Belgium number plates (1-abc-001) and they will run out in the year 11990 somewhere lol... The problem is, that Ipv6 is over engineered, and had no proper transition from Ipv4 > Ipv6 build in, and that is why 30 years later, we are still dealing with the fallout.

imoverclocked 9mo ago

I think this is defeatist talk where it’s not warranted. I remember IPX networks in the 90s were still a thing because people believed they could eke out a little more performance for their games. It’s taking a long time to move to IPv6 in some parts of the world. eg: anyone who doesn’t feel the pain of the IPv4 address crunch likely due to having a large chunk to begin with. Many influential organizations in North America definitely fall in that category. IPv6 is a success IMHO because it is used in so many places. Google’s IPv6 traffic graph shows close to 50% adoption and still trending up. We can’t possibly expect the world to be near 100% overnight… the internet is a big place with the whole spectrum of humans influencing IT; There will always be someone who will cling to IPv4 for dear life.

thayne 9mo ago

I actually think it would have had a better chance of success if ipv6 had embraced the breaking changes to add some killer feature that would have made it worthwhile to upgrade even for entities who didn't need to worry about running out of ipv4 addresses. I'm not sure what that feature would be though.

imoverclocked 9mo ago
This is actually unwanted in a dual-stack world. Once you have divergent behaviors on your networks, you have a complex/weakened security model. Networking should be boring.

Asooka 9mo ago

I've been thinking we could simply extend the ipv4 address to be 11 bytes by (ab)using the options field. That is, add an option that holds more bytes for the source and destination address, which are to be appended to the address already present in the header. I am thinking that since an option starts with 2 bytes and everything must be padded to a multiple of 4 bytes, we can add 16 bytes to the packet, which would hold 7 extra address bytes per source and destination, giving us 11 byte addresses. ISPs would be given a bunch of 4-byte toplevel addresses and can generate 7-byte suffixes dynamically for their subscribers, in a way that is almost the same as CGNAT used today but without all the problems that has. Most routers will only need to be updated to pass along the option and otherwise route as normal, because the top level address is already enough to route the packet to the ISP's routers. Then only at the edge will you need to do extra work to route the packet to the host. Not setting the option would be equivalent to setting it to all 0s, so all existing public hosts will be automatically addressable with the new scheme. There will of course need to be a lot more work done for DNS, DHCP, syntax in programs, etc, but it would be a much easier and more gradual transition than IPv6 is demanding.

fruitworks 9mo ago
I don't think so. It would be more confusion because no one will know if a network is ipv4 or ipv4+, leading to edge case bugs and confusion and people will similarly be lazy and choose to only implement ipv4 knowing it will always be reverse compatible and the cost is transferred to the consumer. Plus, it's only 2048x the address space. It's within the realm of possibility that we will need to upgrade again once this place is swarming with robots.
- GordonS 9mo ago
  x2048 is a lot though! Maybe we should let the robots figure out their own solution, rather than trying to make every atom on Earth individually addressable :)

bit_logic 9mo ago

This whole discussion reminds me of the beautiful design of UTF-8. They used the lower bits to be ASCII which made backwards compatibility so much easier. It also reminds me of the failure of Intels Itanium and the success of AMD x64. Engineers often want to abandon backwards compatibility to make a new "beautiful" design, but it's the design that has full backwards compatibility that's actual impressive.

krupan 9mo ago
So well said! Those are great comparisons.
x0x0 9mo ago
It reminds me of python 3. Basically, a huge chunk of people (in my case, scientific programming) get an enormous mess and nothing at all of value until... 3.6 maybe (the infix matrix mult operator). Stunningly, people weren't enthused about this deal.
liquidpele 9mo ago
It would maybe be okay at the router to break some things, but ffs even in software I have to choose? Why do I need both ping and ping6 this is stupid!! They really screwed up by making it a breaking change to the OS and not just internet routing.
- elcritch 9mo ago
  The whole ping vs ping6 seems more likely than lazy developers.
- Dagger2 9mo ago
  They didn't screw up. They made it a breaking change to OSs because it had to be a breaking change to OSs. If anyone screwed up here, it was the people who made v4, not the ones that made v6. For ping, I think it originally had different binaries because ICMPv4 and ICMPv6 are different protocols, but Linux has had a dual-stack `ping` binary for a very long time now. You can just use `ping` for either address family.

vachina 9mo ago

Truth is there are too many devices that only speak IPv4 or have untested IPv6 stack. People still can’t even agree on how ipv6 address is represented.

iov6throwaway 9mo ago
People have totally agreed on how IPv6 addresses are represented.